Sounds like you had a pretty poor adviser but i dont think they are trying to entrap people into paying too little tax to get fines, morality aside, the maths doesnt add up as they would only enquire into a small proportion of tax returns so most of the people they 'entrapped' in this way would get away with it. Also, if you've received incorrect advice from them leading to an underpayment then this is a valid excuse so you would have to pay the tax but no penalty
Hard to comment on the specifics - if you made a loss then you may indeed not get any tax back - that would depend on if you had other taxable income eligible to absorb any of the losses. I'm surprised they produced a leaflet saying accountants fees are not deductible, but then some accountants fees aren't deductible - it depends what the accountant was advising about
I thoroughly agree with your last paragraph. They are getting better at advising new businesses though - how recently was your advice?
Also, as demonstrated by Kev's question, there often isnt a simple answer to "can i claim for this?" - especially for small start ups where a lot of expenses will have duality of purpose
Can i ask why you just didnt get an accountant to do your return?